Bvanommen battery level

QBeadVisualisation.html

@@ -27,6 +27,7 @@
         </div>
 
         <h3>Live Output</h3>
+        <p id="batteryLevel"></p>
         <div id="output" class="output" style="display: inline;">
           <div id="content"></div>
           <div id="status"></div>
@@ -313,14 +314,16 @@ <h3>Live Output</h3>
             var accCharacteristic;
             var sphCharacteristic;
             var colCharacteristic;
+            var batteryLevelCharacteristic;
 
             function onStartButtonClick() {
               let serviceUuid = "e30c1fc6-359c-12be-2544-63d6aa088d45";
 
               let accUuid = "e30c1fc9-359c-12be-2544-63d6aa088d45";
               let sphUuid = "e30c1fc8-359c-12be-2544-63d6aa088d45";
               let colUuid = "e30c1fc7-359c-12be-2544-63d6aa088d45";
-
+              let batUuid = "00002a19-0000-1000-8000-00805f9b34fb";
+
               log('Requesting Bluetooth Device...');
               navigator.bluetooth.requestDevice(
                 {
@@ -338,6 +341,13 @@ <h3>Live Output</h3>
               .then(service => {
                 log('Getting Characteristics...');
                 service.getCharacteristic(colUuid).then(ch => {colCharacteristic=ch;});
+                service.getCharacteristic(batUuid).then(ch => {
+                    batteryLevelCharacteristic=ch;
+                    return batteryLevelCharacteristic.startNotifications().then(_ => {
+                        batteryLevelCharacteristic.addEventListener('characteristicvaluechanged',
+                      handleBatteryNotifications);
+                    })
+                });
                 return service.getCharacteristic(accUuid);
               })
               .then(characteristic => {
@@ -365,6 +375,17 @@ <h3>Live Output</h3>
                   log('Argh! ' + error);
                 });
               }
+              if (batteryLevelCharacteristic) {
+                batteryLevelCharacteristic.stopNotifications()
+                .then(_ => {
+                  log('> Notifications stopped');
+                  batteryLevelCharacteristic.removeEventListener('characteristicvaluechanged',
+                      handleBatteryNotifications);
+                })
+                .catch(error => {
+                  log('Argh! ' + error);
+                });
+              }
             }
 
             function onPhiRangeChange() {
@@ -408,6 +429,12 @@ <h3>Live Output</h3>
               window.z = z;
               log(`> ${x.toFixed(3)} ${y.toFixed(3)} ${z.toFixed(3)} ${t.toFixed(0)} ${p.toFixed(0)} `);
             }
+
+            function handleBatteryNotifications(event) {
+              let batteryPercentage = event.target.value.getInt8(0);
+              document.getElementById("batteryLevel").textContent = `Battery Level:  ${batteryPercentage}%`;
+              // log(`> ${batteryPercentage} `);
+            }
             </script>
 
 

examples/Tap_to_Measure/Tap_to_Measure.ino

@@ -28,6 +28,8 @@ void setup() {
 // The loop function is called repeatedly until the Qbead is powered off.
 // It is used to read the IMU and update the current state of the game.
 void loop() {
+  bead.measureBattery();
+
   static long last_tap = 0;
   static uint32_t tap_color = white;
 

src/Qbead.h

@@ -8,6 +8,8 @@
 #include <math.h>
 
 #include <bluefruit.h>
+#include <QbeadBattery.h>
+
 
 // default configs
 // TODO make them ifndef
@@ -288,19 +290,24 @@ class Qbead {
         blecharcol(QB_UUID_COL_CHAR),
         blecharsph(QB_UUID_SPH_CHAR),
         blecharacc(QB_UUID_ACC_CHAR),
-        blechartap(QB_UUID_TAP_CHAR)
+        blechartap(QB_UUID_TAP_CHAR),
+        blecharbatlvl(UUID16_CHR_BATTERY_LEVEL)
         {}
 
   static Qbead *singletoninstance; // we need a global singleton static instance because bluefruit callbacks do not support context variables -- thankfully this is fine because there is indeed only one Qbead in existence at any time
 
   LSM6DS3 imu;
+
+  XiaoBattery battery;
+
   Adafruit_NeoPixel pixels;
 
   BLEService bleservice;
   BLECharacteristic blecharcol;
   BLECharacteristic blecharsph;
   BLECharacteristic blecharacc;
   BLECharacteristic blechartap;
+  BLECharacteristic blecharbatlvl;
   uint8_t connection_count = 0;
 
   const uint8_t nsections;
@@ -309,6 +316,7 @@ class Qbead {
   const uint8_t phi_quant;
   const uint8_t ix, iy, iz;
   const bool sx, sy, sz;
+  uint8_t bat_buff[1];
   float rbuffer[3];
   float whentapped_buffer[3];
   float x_whentapped, y_whentapped, z_whentapped; // set when wasTapped is called
@@ -425,9 +433,32 @@ class Qbead {
     blechartap.setFixedLen(3*sizeof(float));
     blechartap.begin();
     blechartap.write(zerobuffer20, 3*sizeof(float));
+    // BLE Characteristic battery level
+    blecharbatlvl.setProperties(CHR_PROPS_READ | CHR_PROPS_NOTIFY);
+    blecharbatlvl.setPermission(SECMODE_OPEN, SECMODE_OPEN);
+    blecharbatlvl.setUserDescriptor("battery level");
+    blecharbatlvl.setFixedLen(1*sizeof(uint8_t));
+    blecharbatlvl.begin();
+    blecharbatlvl.write(zerobuffer20, sizeof(uint8_t));
     startBLEadv();
   }
 
+  void measureBattery(){
+    // if you measure the voltage twice in a row, the second time, the voltage will be 0.2V lower.
+    float percentage = battery.GetBatteryLevel();
+
+    float voltage = battery.GetBatteryVoltage();
+    bool charging = battery.IsChargingBattery();
+    bat_buff[0] = uint8_t(percentage);
+    Serial.println("battery voltage");
+    Serial.print(voltage);
+    Serial.print(", ");
+    Serial.print(charging);
+    Serial.print(", ");
+    Serial.println(percentage);
+    blecharbatlvl.notify(bat_buff, sizeof(uint8_t));
+  }
+
   void clear() {
     pixels.clear();
   }

src/QbeadBattery.h

@@ -0,0 +1,45 @@
+#include <Arduino.h>
+#include <bluefruit.h>
+
+#define BAT_HIGH_CHARGE 22  // HIGH for 50mA, LOW for 100mA
+#define BAT_CHARGE_STATE 23 // LOW for charging, HIGH not charging
+
+class XiaoBattery {
+public:
+  XiaoBattery();
+  float GetBatteryVoltage();
+  bool IsChargingBattery();
+  float GetBatteryLevel();
+private:
+  // define min and max voltage for battery level determination
+  float maxVoltage = 4.11;
+  float minVoltage = 3.06;
+};
+
+XiaoBattery::XiaoBattery() {
+  pinMode(VBAT_ENABLE, OUTPUT);
+  pinMode(BAT_CHARGE_STATE, INPUT);
+
+  digitalWrite(BAT_HIGH_CHARGE, LOW); // charge with 100ma if LOW, else 50mA
+}
+
+#define VBAT_MV_PER_LBS (0.003395996F)
+
+float XiaoBattery::GetBatteryVoltage() {
+  digitalWrite(VBAT_ENABLE, LOW);
+  // might want to wait very briefly for the voltage to settle
+  uint32_t adcCount = analogRead(PIN_VBAT);
+  float adcVoltage = adcCount * VBAT_MV_PER_LBS;
+  float vBat = adcVoltage * (1510.0 / 510.0);
+
+  digitalWrite(VBAT_ENABLE, HIGH);
+
+  return vBat;
+}
+
+float XiaoBattery::GetBatteryLevel() {
+  float batPercentage = (GetBatteryVoltage()-minVoltage)/(maxVoltage - minVoltage) * 100;
+  return batPercentage;
+}
+
+bool XiaoBattery::IsChargingBattery() { return digitalRead(BAT_CHARGE_STATE) == LOW; }